There are multiple sub_id for same other values , meaning - On Monday 1st hour, 5th B students might have 2 or more lab (sub_id). (Its conducted in batches).

To get a proper timetable, I am doing this :

select day,
max( case when hour =1 then sub_id end ) as 'hour-1',
max( case when hour =2 then sub_id end ) as 'hour-2',
max( case when hour =3 then sub_id end ) as 'hour-3',
max( case when hour =4 then sub_id end ) as 'hour-4',
max( case when hour =5 then sub_id end ) as 'hour-5',
max( case when hour =6 then sub_id end ) as 'hour-6',
max( case when hour =7 then sub_id end ) as 'hour-7',
max( case when hour =8 then sub_id end ) as 'hour-8'
from master
where sem=5 and sec='B'
group by day
order by day;

select day,
group_concat( case when hour =1 then sub_id end ) as 'hour-1',
group_concat( case when hour =2 then sub_id end ) as 'hour-2',
group_concat( case when hour =3 then sub_id end ) as 'hour-3',
group_concat( case when hour =4 then sub_id end ) as 'hour-4',
group_concat( case when hour =5 then sub_id end ) as 'hour-5',
group_concat( case when hour =6 then sub_id end ) as 'hour-6',
group_concat( case when hour =7 then sub_id end ) as 'hour-7',
group_concat( case when hour =8 then sub_id end ) as 'hour-8'
from master
where sem=5 and sec='B'
group by day
order by day;